A method for producing refined loose wet industrial salt based on downhole recycling of waste liquid

Abstract

The invention discloses a method for producing refined moisture diffusion industrial salt based on underground recycling of waste liquid. The method comprises the following steps: (1) mixing waste water of salt production with ammonia alkali waste liquid in proportion; (2) injecting the mixed waste liquid obtained in step (1) into an underground mirabilite type rock salt cavern; after sufficient reaction and natural sedimentation, extracting low-nitrate brine; (3) injecting the low-nitrate brine obtained in step (2) into a reaction barrel, injecting a sodium carbonate solution into the barrel, and adding a certain amount of sodium polyacrylate as a coagulant aid; then, stirring and standing, and removing calcium ions out of the brine to obtain refined low-nitrate brine; (4) carrying out secondary preheating on the refined low-nitrate brine obtained in the step (3), carrying out evaporation, concentration, crystallization and solid-liquid separation, and carrying out centrifugal separation on underflow salt slurry to obtain a refined moisture diffusion industrial salt product; (5) with liquid obtained by solid-liquid separation and centrifugal separation in the step (4) as the waste water of salt production, supplying the waste water into the step (1), blending the waste water with the ammonia alkali waste liquid in proportion, and injecting the mixture into the underground rock salt cavern as a brine extracting source, thus realizing the recycling of waste liquid.

Description

technical field [0001] The invention belongs to the field of salt products, and in particular relates to a method for producing refined wet industrial salt based on downhole recycling of waste liquid Background technique [0002] In recent years, the production capacity and market demand of my country's two major industries of soda ash and caustic soda have grown rapidly, and China has become the world's largest producer and consumer. As the leading industry of raw salt consumption in my country, the rapid development of the two alkali industries has driven and stimulated the rapid expansion of raw salt production scale. In 2012, the total consumption of raw salt in my country reached 86.6 million tons, of which 70.75 million tons were used in the soda ash and caustic soda industries, accounting for 81.7% of the total national salt consumption. From the perspective of raw salt production capacity, the proportion structure of well mine salt production has continued to increa...

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Problems solved by technology

The water quality of the secondary steam condensate has a lot to do with the process control. For the salt production device using the multi-effect evaporation salt production process, the total salt content index in the final effect mixed condensate is usually 500mg / l~1600mg / l l, the index of chloride ion is usually 200mg / l~800mg / l, and the temperature is usually 40℃~70℃. Although there are many ways of recycling, such as supplementary water for circulating cooling water or cooling water for equipment, its relatively high Chloride content and higher temperatures often limit the use of mixed condensate

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